A thermal printer is known which melts the ink of a transfer ribbon using heat generating elements of a thermal head to transfer the ink to a sheet. The thermal printer conveys the transfer ribbon and the sheet at the same speed while pressing the transfer ribbon against the sheet using the thermal head. In this state, the thermal printer carries out printing on the sheet using the thermal head through the transfer ribbon.
In the thermal printers, there is a thermal printer comprising a ribbon saving mode. In the mode, if a non-print area length in a conveyance direction in the printing data exceeds a given value, the printer stops conveying the transfer ribbon and conveys the sheet merely in the non-print area. Further, the printer heads up the thermal head to separate the thermal head from the sheet, so as to separate the transfer ribbon from the sheet. In this way, in the ribbon saving mode, the consumption amount of the transfer ribbon in the non-print area can be restricted.
The printer heads down the thermal head to return the thermal head to an original printable position, and meanwhile restarts the conveyance of the transfer ribbon before the sheet is conveyed for the length of the non-print area.
By the way, to carry out a ribbon saving processing including the heading up and the heading down, it is necessary that there be non-print area length corresponding to the printing speed (conveyance speed of the sheet) in the printing data. However, the required non-print area length varies for different physical properties of the transfer ribbon for each printing speed. Thus, conventionally, in order to achieve a specific printing quality no matter what kind of transfer ribbon is used, the setting value of the required non-print area length is set as the maximum non-print area length within the non-print area lengths which differ for each physical property.
Thus, there is a problem that the conventional printer cannot carry out the ribbon saving processing if the non-print area length in the printing data is less than the set non-print area length (the maximum non-print area length within the non-print area lengths which vary for different physical properties), even if the non-print area length in the printing data is greater than the required length with respect to the printing speed and the physical property of the transfer ribbon.